offset of the first 0x01 byte // invalid: 1 iff we saw a non-zero byte before the 0x01. var lookingForIndex, index, invalid int lookingForIndex = 1 rest := db[hash.Size():] for i := 0; i < len(rest); i++ { equals0 := constanttime.ByteEq(rest[i], 0) equals1 := constanttime.ByteEq(rest[i], 1) index = constanttime.Select(lookingForIndex&equals1, i, index) lookingForIndex = constanttime.Select(equals1, 0, lookingForIndex) invalid = constanttime.Select(lookingForIndex&^equals0, 1, invalid) } if firstByteI...